Apparatus is known for sterilization by steam of fermentation objects (cf. the U.S. Pat. No. 3,445,341; dated 1969), comprising a sealed chamber--sterilization vessel adapted to contain a solution under investigation, the vessel receiving therein a heater and means for stirring the solution. The sterilization vessel is further provided with a heat exchanger mounted on its surface and adapted to stabilize the selected temperature of the solution under investigation, and also with the inlet and outlet pipes, respectively, for feeding and discharging the solution under investigation.
The operating principle of this prior art apparatus is based on heating the solution contained in the sealed chamber by the heat radiated by the heater which, in its turn, receives its energy from an external steam source. By the development of steam through the heating of the investigated solution a gauge pressure in excess of the atmospheric one is built up within the sealed chamber. A predetermined temperature is maintained within the sealed chamber with aid of a cooling/heating agent circulated through the heat exchanger. The sterilization of the internal space of the sealed chamber takes place simultaneously with the sterilization of the solution contained therein, and when microorganisms are subsequently grown in the chamber, the latter is used as a fermenter.
The prior art apparatus for sterilization by steam of fermentation objects offers only a limited range of applications for research purposes, requiring as it does for its operation an external source of steam. Besides, when a fluid medium is being sterilized, its concentration is varied on account of the condensation of steam in the solution which has a lower temperature.
In the practice of growing microorganisms, it is required more often than not to compose complex nutrient media including various components capable of forming insoluble sediments as the temperature is raised. The general practice in such cases is to sterilize the individual components of the media separately, so as not to vary the concentration of the initial medium. The apparatus of the prior art, however, cannot be used for such separate sterilization of solution, since the sterilization vessel has a unitary volume, so that every new medium added for sterilization would be subjected to the heat treatment jointly with the previously sterilized media, thus forming a complex solution capable of forming a sediment.
Moreover, with the medium including heat-effected components, e.g. glucose, requiring a lower sterilization temperature, the treatment in the prior art apparatus might result in the caramelization of such components, which likewise affects the concentration of the initial medium.
The apparatus of the prior art is inoperable in the process of growing microorganisms continuously, when the continuous supply of a sterile medium into the fermenter is required, because in the course of the fermentation the sterilization vessel operates as the fermenter and would not perform the function of the sterilizer. The apparatus of the prior art is operable for sterilizing fermentation objects, e.g. pumps for feeding a culture suspension, fluid-metering devices, various sensors and connection lines incorporated in the structure of the apparatus itself; however, it cannot be used for sterilizing other fermenters and equipment for supporting fermentation processes. The above factors narrow the range of the applications of the apparatus.
It is an object of the present invention to create an apparatus for sterilization by steam of various fermentation apparatus, e.g. fermenters, communication lines with valves, etc. It is another object of the present invention to provide for sterilization by steam of various liquid nutrient media used both in intermittent and continuous modes of growing microorganisms, while maintaining the initial concentration of such media.
It is still another object of the present invention to provide for sterilization by steam of gas filters.